Tonks sees an advantage, when she has the chance to "rescue" her annoying cousin. Kingsley supports her for his very own motives, and even her mother feels the need to help. Mad-Eye Moody is the only one who can see the danger of having a "Junior-Deatheater" amongst them.
But while the ministry is being infiltrated and the wizarding world suffers from great losses like the current death of Albus Dumbledore, nobody listens to him...